AB0689 Clinical courses and pregnancy outcomes of eight cases complicated with Polymyositis/Dermatomyositis (PM/DM) in single center
Authors: R. Mino, H. Shimada, R. Wakiya, S. Nakashima, M. Kato, T. Miyagi, K. Sugihara, Y. Ushio, M. Mizusaki, T. Kameda, H. Dobashi
Journal: Annals of the Rheumatic Diseases (2022)

Background Pregnancies complicated by a number of rheumatic diseases are known to be at high risk for the occurrence of adverse pregnancy outcomes (APOs). There have been several reports on the risk of APOs in systemic lupus erythematosus and rheumatoid arthritis, but few reports on polymyositis (PM)/dermatomyositis (DM) pregnancies. There are also insufficient reports on changes in the activity of PM/DM during pregnancy. Based on the findings reported in other rheumatic diseases, it is suggested that increased activity during pregnancy is associated with APOs in PM/DM (1-3). However, the risk factors for pregnancy outcome in pregnancies complicated by PM/DM, including the presence or absence of worsening of disease activity, have not been clarified. Objectives The purpose of this study was to analyze a case series of PM/DM complicated pregnancies in a single center to determine the changes in disease activity during pregnancy and pregnancy outcomes. Methods PM/DM patients who were managed from pregnancy to delivery at Kagawa University Hospital from March 2006 to May 2021 were included in this study. Clinical indices including duration of illness, disease activity, and treatment were extracted from medical records and retrospectively analyzed for association with pregnancy outcome. Results Eight PM/DM pregnancies were included in the analysis. The mean age at delivery was 28.3±3.8 years and the mean duration of disease was 6.3±3.2 years. Treatment at the time of pregnancy included glucocorticoids (GC) in 7 cases and immunosuppressive drugs in 5 cases. Creatinine phosphokinase (CK) levels were normal in all patients at the time of pregnancy, but increased during pregnancy in 4 (50%) patients. These 4 patients with elevated CK required treatment with increasing doses of GC, and the mean GC dose during pregnancy was 10.9 ± 6.0 mg/day. Table 1 shows the pregnancy outcomes of the 8 patients. There was one spontaneous abortion and seven live births. Among the live births, 2 were preterm and 4 were low birth weight. The mean gestational age at delivery was 35.3±5.2 weeks and the mean birth weight was 2297.7±1041.4g. Table 1. Pregnancy outcomes of eight cases Case no. Outcome Mode of delivery Gestational age at delivery (weeks) Birth weight of the newborn (grams) Adverse pregnancy outcomes 1 Live birth Cesarean section 26 590 Preterm birth, LFD, HELLP syndrome 2 Spontaneous abortion 3 Live birth Transvaginal delivery 30 1,299 Preterm birth, LBW 4 Live birth Cesarean section 38 2,765 Hypertensive disorder 5 Live birth Transvaginal delivery 37 3,290 − 6 Live birth Transvaginal delivery 37 2,492 LBW 7 Live birth Transvaginal delivery 39 3,456 − 8 Live birth Transvaginal delivery 40 2,192 LBW 7 live births 1 abortion 35.3±5.2 2,297.7±1,041.4 The birth outcomes of the 2 patients who received continuous immunosuppressive therapy were full-term and normal weight infants. APOs, such as preterm delivery and low birth weight, occurred in cases with increased CK levels and increased GC doses. Conclusion In pregnancies of PM/DM patients, pregnancy outcome was less than favorable. An association between disease activity and the development of APOs during pregnancy in PM/DM was suggested. An association was also suggested between GC dose and the risk of developing APOs. As in other rheumatic disease pregnancies, continued use of pregnancy-appropriate immunosuppressive drugs and control of disease activity with lower glucocorticoid doses in PM/DM pregnancies may be important to achieve good pregnancy outcomes. References [1]Nagy-Vincze M, Vencovsky J, Lundberg IE, Danko K (2014) Pregnancy outcome in idiopathic inflammatory myopathy patients in a multicenter study. J Rheumatol 41:2492-2494. [2]Zhong Z, Lin F, Yang J, Zhang F, Zeng X, You X (2017) Pregnancy in polymyositis or dermatomyositis: retrospective results from tertiary centre in China. Rheumatology (Oxford) 56:1272-1275. [3]Kolstad KD, Fiorentino D, Li S, Chakravarty EF, Chung L (2018) Pregnancy outcomes in adult patients with dermatomyositis and polymyositis. Semin Arthritis Rheum 47:865-869. Disclosure of Interests None declared